Throw exception when library for RuntimeUtils is missing

Author: Marcono1234

src/main/java/ca/weblite/nativeutils/NativeUtils.java

@@ -25,40 +25,44 @@ private NativeUtils() {
     }
 
     /**
-     * <p>loadLibraryFromJar.</p>
+     * Loads a library from current JAR archive, using the class loader of the {@code NativeUtils}
+     * class to find the resource in the JAR.
      *
      * @param path a {@link java.lang.String} object.
      * @throws java.io.IOException if any.
+     * @throws UnsatisfiedLinkError if loading the native library fails.
      */
     public static void loadLibraryFromJar(String path) throws IOException {
         loadLibraryFromJar(path, NativeUtils.class);
     }
 
     /**
-     * Loads library from current JAR archive
+     * Loads a library from current JAR archive.
      *
      * The file from JAR is copied into system temporary directory and then loaded. The temporary file is deleted after exiting.
      * Method uses String as filename because the pathname is "abstract", not system-dependent.
      *
      * @throws java.lang.IllegalArgumentException If the path is not absolute or if the filename is shorter than three characters (restriction of @see File#createTempFile(java.lang.String, java.lang.String)).
      * @param path a {@link java.lang.String} object.
-     * @param source a {@link java.lang.Class} object.
+     * @param source {@code Class} whose class loader should be used to look up the resource in the JAR file
      * @throws java.io.IOException if any.
+     * @throws UnsatisfiedLinkError if loading the native library fails.
      */
-    public static void loadLibraryFromJar(String path, Class<?> source) throws IOException {
+    public static void loadLibraryFromJar(String path, Class<?> source) throws IOException, UnsatisfiedLinkError {
         // Finally, load the library
-        System.load(loadFileFromJar(path, source).toAbsolutePath().toString());
+        System.load(extractFromJar(path, source).toAbsolutePath().toString());
     }
 
     /**
-     * <p>loadFileFromJar.</p>
+     * Extracts a resource from the JAR and stores it as temporary file
+     * in the file system.
      *
-     * @param path a {@link java.lang.String} object.
-     * @param source a {@link java.lang.Class} object.
+     * @param path path of the resource, must begin with {@code '/'}, see {@link Class#getResourceAsStream(String)}
+     * @param source {@code Class} whose class loader  should be used to look up the resource in the JAR file
      * @return file path of the temporary file extracted from this JAR
      * @throws java.io.IOException if any.
      */
-    public static Path loadFileFromJar(String path, Class<?> source) throws IOException {
+    public static Path extractFromJar(String path, Class<?> source) throws IOException {
         if (!path.startsWith("/")) {
             throw new IllegalArgumentException("The path has to be absolute (start with '/').");
         }

src/main/java/ca/weblite/objc/RuntimeUtils.java

@@ -1,7 +1,9 @@
 package ca.weblite.objc;
 
 
-import ca.weblite.nativeutils.NativeUtils;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+
 import com.sun.jna.Pointer;
 import com.sun.jna.ptr.ByReference;
 import com.sun.jna.ptr.ByteByReference;
@@ -11,7 +13,8 @@
 import com.sun.jna.ptr.LongByReference;
 import com.sun.jna.ptr.PointerByReference;
 import com.sun.jna.ptr.ShortByReference;
-import java.io.IOException;
+
+import ca.weblite.nativeutils.NativeUtils;
 
 /**
  * A Java class with static methods that interact with the Objective-C runtime.
@@ -45,28 +48,16 @@ private RuntimeUtils() {
 
     }
 
-    /**
-     * Flag to indicate whether the jcocoa native library was loaded successfully.
-     * If it fails to load, then this flag will be false.  Therefore, if this
-     * flag is false, you shouldn't try to use the the api at all.
-     */
-    private static boolean loaded = false;
     static {
+        String libraryPath = "/libjcocoa.dylib";
         try {
-            //System.loadLibrary("jcocoa");
-            NativeUtils.loadLibraryFromJar("/libjcocoa.dylib");
-            loaded = true;
-        } catch (UnsatisfiedLinkError err){
-            err.printStackTrace(System.err);
-        } catch (IOException ex) {
-            ex.printStackTrace(System.err);
+            NativeUtils.loadLibraryFromJar(libraryPath);
+            init();
+        } catch (IOException ioException) {
+            throw new UncheckedIOException("Failed loading library " + libraryPath, ioException);
         }
-        init();
     }
 
-    
-    
-    
     /**
      * Returns a pointer to the class for specific class name.
      * <pre>
@@ -886,7 +877,7 @@ public static ByReference getAsReferenceWrapper(Object val, String signature){
      * Initializes the libjcocoa library.  This is called when the class is first
      * loaded.  It sets up the JNI environment that will be used there forward.
      */
-    public static native void init();
+    private static native void init();
 
     /**
      * Registers a Java object with the Objective-C runtime so that it can begin